This invention pertains to apparatus for false twisting yarn, principally continuous multiple-filament synthetic yarn, such as to texturize or to impart certain physical characteristics thereto. In the type of apparatus to which the present invention in its broadest aspects in directed, such apparatus usually involves the heat setting of the false twist in the yarn, there often later being a removal of the false twist, after a cooling of the twisted yarns, such that the yarns take on a texturized, natural fiber appearance and character.
More particularly, this invention pertains to a conventional, industrially acceptable multiple-station twisting machine improved by the incorporation therein of an array of stabilized friction twisting members so that the twisting effectiveness and speed of the machine are greatly enhanced.
It is well known that synthetic yarn may be texturized or modified in its physical characteristics by false twisting the yarn and heat setting it while it is in the false twisted condition, all as the yarn is passed continuously through the false twisting and heat setting processes.
A substantial number of these existing machines impart false twist to the yarn by passing the yarn about a spindle mounted on a rotating shaft. In most cases, the spindle extends across a hollow shaft and the yarn is guided from above about the spindle and down through the vertically disposed hollow shaft to a further guide and take up means, while the spindle at each work station is held, such as by magnetic force, in engagement with discs on vertically disposed rotating shafts in frictional engagement with an endless member, such as a moving belt, passing along all of the stations of a multi-station machine. Because of the normal friction in such machines in the tortuous path that the yarn takes about the revolving spindle (often called a spindlette), these machines are necessarily limited in either the speed at which they can false twist the yarn, particularly the speed of rotation of the shaft upon which the spindle is mounted, or the effectiveness with which yarn can be false twisted at any given lineal yarn speed or both.
In U.S. Pat. No. 3,705,488, of which the present applicant is a co-inventor, an improved friction twister, consisting of an array of stabilized rotating friction twisters, was fully disclosed. This type of twister has the capability for effectively imparting a false twist, at a reasonably high rate of twist, to yarn passing through the apparatus at a relatively high velocity, such that a given level of false twist may be imparted to yarn passing through the device at a much higher speed than is possible in typical prior art false twisters, particularly including those based on a revolving spindle. However, the friction twister disclosed in U.S. Pat. No. 3,705,488 was horizontally disposed and rotation was imparted thereto by a friction driving member mounted on a shaft rotated from one end of the machine. This driving means and general disposition of the apparatus, as disclosed in U.S. Pat No. 3,705,488 is in some respects unnecessarily complex and involves a yarn path which requires that each yarn treatment station be somewhat wider than might otherwise be desired.
With this in mind, it is one general object of the present invention to enhance greatly the twisting effectiveness and the speed at which yarn can be treated in a variety of multi-station false twisting machines.
It is a more specific object of this invention to increase the speed capability of conventional revolving spindle-type multistation false twisting machines.
Additionally, multiple-station machines known in the art generally comprise a plurality of stations, and with the twist-inducer being driven at the same speed from station-to-station, either separately, or by a common driving member, such as a driving belt. Each of these stations provides a single yarn strand, and from station-to-station, it has been found that there are often very slight minor discrepancies in the degree of twist of the yarn. The reason for this can be slight differences in the yarn prior to its treatment, or can be the result of slight differences in physical structures of the twist-inducers, or as the result of wear of various parts of the twist-inducers, or otherwise, variations in the numbers of turns per lineal inch (or amount of twist) can exist.
When discrepancies exist, from station-to-station, the yarns provided thereby of course differ slightly one from the other. In constructing a fabric from these yarns, it occasionally happens that one or more of the yarns that make up a given piece of fabric have a different number of turns per inch, that results in different physical characteristics of that particular yarn from the others making up the fabric.
A principal area in which discrepancies from yarn-to-yarn is disadvantageous, is in the subsequent processing of the fabric, most especially, in the dyeing of the fabric. Yarns that have different physical characteristics, having been twisted more or less than other yarns in the fabric, and having been additionally heat-set, or otherwise additionally texturized, may absorb a greater or less amount of dye than other, for example, adjacent yarns. The result of this is that dye streaking occurs, leaving a fabric that can be unacceptable for unevenness in coloring, or having the appearance of lines located therein, in sporadic fashion, wherever yarns or yarn portions exist that have dissimilar characteristics as set forth hereinabove, from other yarns in that fabric.
Accordingly, it is an additional object of this invention to provide some means of eliminating inconsistencies in degree of twist in yarn from station-to-station.
Also, because even in a single station arrangement, in the event that twist-inducing components of a friction twister are subjected to wear during usage, it becomes desirable to provide some means for compensating for this year. It is therefore another object of this invention to provide a means for compensating for such wear, in order to provide yarn having consistent characteristics, and especially to provide yarn from a friction twister that is consistent in desired number of turns per inch, and to this end an adjustment means is provided for adjusting the amount of twist that a friction twister will apply to yarn being treated thereby.
Similarly, it is an object of this invention to provide a means whereby friction twisters at the various stations on a multiple-station machine may be periodically adjusted, by first measuring the amount of twist being applied to the yarn at the various stations, and by then making appropriate adjustments such that all stations provide the same degree of twist, for uniformity in the yarns from station-to-station.
In friction twisting devices presently available, if it is desired to compensate for wear of the devices, or to make some minor adjustment in the devices to alter the amount of twist being applied to yarn being mechanically treated thereby, it has been necessary to interrupt the operation of the friction twister, as by shutting down the machine, and then to dissassemble the devices, applying the appropriate shims, washers or the like to obtain alterations in spacing. Such manner of effecting adjustments is haphazard at best, can be time-consuming, result in lost production time, and in general is made only with substantial difficulty. Also, it has been found that in friction twisting devices presently available, yarn tension has an influence on the amount of twist being applied. From station-to-station slight differences in twist-inducing mechanisms due to tolerance discrepancies or otherwise can result in variations in yarn tension from station-to-station. These variations may or may not be acceptable, depending upon their influence on twist. Tension influence on twist can also vary with the yarn denier. The present invention allows for compensation for tension variations by adjustment of the amount of twist.
It is accordingly a further object of this invention to provide a means for effecting adjustment of the degree of twist being applied by a friction twister, during the running of the machine, without requiring disassembly.
Some of the objects set forth above are met, in accordance with the present invention by an improved multi-station machine wherein each station includes conventional yarn supply, yarn take-up and guide means, with the usual false twist stopping means, yarn heater, and yarn forwarding means with an endless member such as a belt which passes along all of the stations of the machine to impart rotary motion to a false twist spindle therein; such machine including a specific improvement to enhance false twist effectiveness and yarn speed through the machine by the incorporation therein of a friction twister consisting of a vertically disposed array of stabilized friction twisters, as specifically described hereinafter, rotated by frictional engagement of one or both of the shafts thereof with the endless member passing along all of the stations of the machine.
For meeting more specific objects of this invention, the stabilized false twisting means consists of an array of mating rotating friction twisters, and freely rotatable stabilizing anvils mounted alternatingly on a pair of vertically disposed shafts with guide means at either ends thereof so that yarn is urged into frictional engagement with the friction twisting member, and biased toward a barrier formed by the mating friction twisting members and stabilizing anvil means. Further, by virtue of the fact that each of the friction twisting members is of larger diameter than the anvil members, the yarn passing between the friction member-anvil member pairs alternatingly disposed on the shafts is urged in each case toward the friction member and toward the barrier formed by the friction members and the mating anvil member, while each of the friction members is rotated such that the moving surface thereof tends to drag the yarn away from that barrier. In this way, a highly effective false twisting means is incorporated in an existing type of machine. This constitutes a tremendous improvement in such machines by virtue of the increased speeds with which such machines can handle the yarn to be treated.
In a further preferred embodiment of the present invention, pairs of such arrays are mounted in paired stations along the length of the machine so that a much larger number of yarns can be handled in a given space.
In other embodiments of the present invention, a false twisting apparatus is provided, that utilizes a friction-applier, and a back-up-member termed an anvil, that define a yarn barrier therebetween. The yarn barrier can be a space less than the thickness of the yarn, or it can reside in the surface of the friction-applying member and the anvil or back-up-member being in surface-to-surface engagement, as desired. In some instances, it will be desired that the anvil and the friction member be in interference fit with one another, in order to assure that the barrier will provice no space for yarn to slip therethrough. In any event, in the broader aspects of some of the embodiments of this invention, some means will be provided for adjusting the amount of twist provided by the friction-inducer, preferably by adjusting the location of the barrier in such a way so to alter the yarn path through the friction twister. In additionally more specific embodiments of this invention, such alteration of the yarn path will be situated to cause the yarn to have a greater or lesser amount of contact with, or degree of wrap about the friction-applying disc, wheel or the like, such that any correspondingly greater or lesser amount of twist is applied to the yarn. Also, in the more preferred embodiments of the invention, such adjustments in degree of twist will be supplied without requiring any change in speed or the yarn twist inducer, without requiring any change in the speed of delivery of yarn along its path, and also without requiring any shut-down of the apparatus while being adjusted.
Additionally, in even more specific forms of that feature of the present invention in which a twist adjustment is provided, there will be multiple sets of friction-applying members and anvil or back-up-members, one or more of which can contain the afore-said adjustment feature, such adjustment feature being either on the friction-applying member, or on the anvil or back-up-member, but preferably being applicable to the latter.
Other objects of the present invention will be readily apparent from an understanding of the brief description of the drawing figures, the detailed descriptions of the preferred embodiments, and the appended claims.